Comprehensive and accurate analysis of soil resistivity is significant to the optimum design of grounding devices. This paper builds soil resistivity measurement models by the CDEGS (Current Distribution, Electromagnetic fields, Grounding and Soil structure analysis) system based on the Wenner fourelectrode method, simulates the soil resistivity of the selfdefined soil structure, and makes inversion analysis to obtain the simulated soil structure parameters. Then by making a comparative analysis between the simulated and defined soil structure parameters, the validity of soil structure inversion analysis is verified. This paper conducts field tests and a comparison of tested grounding resistance and simulated grounding resistance to validate the validity of soil structure and grounding resistance inversion analysis. In addition, the effect of vertical and horizontal grounding devices on grounding resistance reducing is discussed simply in the situation of twolayer soil structure. The results indicate that the system can obtain the real and comprehensive soil structure and grounding resistance，which has a great importance to the design of grounding device and the assessment of grounding resistance.